diff --git a/contrib/compiler-rt/lib/builtins/clear_cache.c b/contrib/compiler-rt/lib/builtins/clear_cache.c
index b7e099dfb2c0..18e18e942c46 100644
--- a/contrib/compiler-rt/lib/builtins/clear_cache.c
+++ b/contrib/compiler-rt/lib/builtins/clear_cache.c
@@ -9,6 +9,7 @@
  */
 
 #include "int_lib.h"
+#include <stddef.h>
 
 #if __APPLE__
   #include <libkern/OSCacheControl.h>